Identify a Public Domain Work

You have selected the Public Domain Certification. The Public
Domain Certification should only be used to certify a work that is
already in the public domain. Creative Commons does not recommend
you use the Public Domain Certification for dedicating a work
still protected by copyright to the public domain. To dedicate a
work to the public domain, consider
using CC0. Please note that if you
use the Public Domain Certification to dedicate a work to the
public domain, it may not be valid outside of the United States.

Once you're done filling this out, you will still have the
opportunity to confirm your choice before the certification
happens.